The moment Microsoft announced it would lock other browsers out of being installed on Windows RT, we all knew regulatory bodies the world over were wringing their hands. Today, this has been confirmed: in the wake of an investigation into Microsoft not complying with the existing antitrust rulings regarding browser choice, the EU has also announced it's investigating Windows 8 x86 and Windows 8 RT (ARM).

I never quite understood why attempts to hit Microsoft with antitrust actions are so focused on the browser (Internet Explorer). Especially now that IE has fallen to less than 50% market share, the EU should be focusing on more relevant issues.

Microsoft is guilty of plenty of rotten things, but the browser "problem" is the tip of the iceberg. Why don't antitrust prosecutors focus on the fact that OEMs are not allowed by Microsoft to install any other OS on their machines. Many manufacturers have wanted to offer a dual-boot computer with Windows and Linux both installed, but Microsoft will have none of it. Microsoft's power rests on the fact that they can charge full retail price for copies of Windows to manufacturers who don't toe the line. In the highly competitive computer market, this is a powerful threat.

When ASUS starting offering the eeePC with Linux only installed, Microsoft had a fit and pulled their leash hard, with the result that now eeePC buyers (like me) are forced to buy a nonrefundable copy of Windows (which I immediately erased, and then installed Linux). This is the well-known "Microsoft tax." Why can't consumers who don't want Windows have to pay for it?

Of course, there is the whole issue of abusing patents. The way Microsoft extracts royalties for unnamed patents that are supposed to be in Android is simply outrageous. Why aren't the antitrust enforcers concerned about that?

Reasons are partially historic. The famous antitrust case against MS was focused on the browser, and while OS bundling was mentioned, and MS even disclosed the fact that they influence OEMs to do this bundling, nothing was ever done about it. I always wondered why, but couldn't really figure it out.

Might want to check your history a little better friend. The Linux EEE PC did not disappear because "MSFT pulled on the chain" but because the company went out of business that was supplying the version they were using and Asus didn't want to build their own distro, not to mention that the tab UI that the EEE was using was proprietary and owned by the company in question, which was Xandros BTW.

Oh and just FYI but the "Windows tax" is in actually a "Windows tax break" because you are taking a machine which OEMs like Asus are paid to put trialware on and then wiping. Have you contacted Asus about writing them a check for the cost difference between what the system would have cost without trialware and what it cost with? didn't think so, but its pretty common knowledge that thanks to companies like Symantec paying to have Norton trial junk installed that Win 7 Start and HP don't cost the OEMs anything, in fact that make money per unit which they use to lower the cost of the system.

I never quite understood why attempts to hit Microsoft with antitrust actions are so focused on the browser (Internet Explorer).

They are not, browsers are just something visible that the public understands and can keep track of, everything you remember evidently... but the other issues you raised (AND MUCH MORE) were and are looked at, they (and not the browsers) were often the subject of heavy fines.